The U.S. Supreme Court’s decision this week to hear arguments on the constitutionality of the one-man-one-vote principle that has been the bedrock of American electoral law for more than half a century raises the possibility that political inequality soon will join economic inequality as one of this harsh era’s bitter facts of life.

If Chief Justice John Roberts’ court voids the principle, as seems likely, the consequences will fall with particular severity on California and other border states with large urban minority and immigrant populations.

The high court delineated the one-man-one-vote standard as part of its ruling in the landmark 1964 case of Reynolds v Sims. Essentially, then-Chief Justice Earl Warren’s court held in that decision that all legislative districts must be of roughly equal size as measured by U.S. Census data. The decision’s immediate implementation remade the face of American politics and generally is considered one of the Warren Court’s most unambiguous successes. Three times in the past two decades, the high court has refused to hear challenges to the principle, but the current court has agreed to weigh a Texas suit — Evenwel v Abbott — that seeks to supplant one-man-one-vote with districts based solely on the number of eligible voters. If that standard supplants one-man-one-vote, political power will shift from urban districts with large minority populations and concentrations of immigrants, both with and without papers. Instead, influence will shift to suburban and rural districts whose populations are whiter, more affluent and older than the nation as a whole.

That’s a tectonic reversal, one that would roll back the rising political power of Latino Americans and severely disadvantage African Americans and the young. California, for example, has elected record numbers of Latinos and blacks to office at all levels — national, state and local — over the past 20 years. That would become a thing of the past, as it would in other Southwestern states, like Arizona, Nevada and Texas.

The right-wing activists of the Roberts court, however, have been anything but shy about reshaping the landscape of electoral law to the Republican Party’s benefit. Two years ago, the conservative bloc basically gutted the historic Voting Rights Act of 1965, when it held the law’s key enforcement mechanisms unconstitutional in the case of Shelby County v Holder. Since then, at least 15 states have either enacted redistricting plans that previously would have been prohibited or pressed ahead with a variety of heretofore illegal voter identification schemes and qualification regulations. They’ve also altered registration and early-voting practices in ways that have dramatically suppressed turnout among minorities and the young. This new Texas suit aims to finish the job on Latinos.

This term, the Roberts court already has heard arguments in Arizona State Legislature v. Arizona Independent Redistricting Commission in which the GOP-dominated legislature is seeking to wrest back the power to draw district lines from a nonpartisan citizens’ group. California also has such a commission, and if the court finds in the Arizona plaintiffs’ favor, we’ll be back to the bad old days of safe seats created by partisan gerrymandering, which almost invariably benefits older, mostly white, males. (Now, which party does that describe?)

To an extent too infrequently acknowledged, 20th Century America’s greatest accomplishment was unprecedented extension of liberty and equality to those previously excluded from their benefits. Women’s suffrage was perhaps the first milestone, followed by the New Deal and the post-war GI Bill and industrial unionization and progressive income taxation, which allowed millions to share in the great economic boom. The civil rights movement followed, as did the women’s movement and the struggle for gay and lesbian rights that is climaxing in the marriage equality push. None of these was wholly successful, but their benefits were enormous and widespread. In this 21st century, all of these things are being — to greater and lesser extents — rolled back.

Income equality unseen since the Gilded Age once again prevails, and the social mobility once taken for granted as part of the post-war American system is now on life support. We’re also moving into a catastrophic inequality of social and economic security. Those at the top of the economic ladder can afford to educate their children in private schools and universities and to save and invest for a secure retirement. Working and middle-class families — insecure in their employment — must send their children to often dysfunctional public schools and to increasingly expensive public colleges and universities whose inadequate number of classes virtually eliminates the prospects of a traditional four-year degree.

Meanwhile, government has looked away as private industry has all but eliminated the defined-benefit pension plans on which most Americans have relied for a secure retirement. Instead, they’ve been thrown onto reliance on 401(k)s that never were intended to be anything but a supplement to pensions and Social Security. At the same time, increasing numbers of large private employers have abandoned yearly raises, thereby exacerbating the stagnation of wages out of which workers are expected to save and invest. The annual incomes of executives and senior managers, meanwhile, have risen to levels never before recorded. Last year, for example, America’s highest paid CEO — Discovery Communication’s David Zaslav — made $156.1 million.

There you have the current situation of most Americans: anxiety over a present in which prospects are uncertain and advancement increasingly difficult and fear over a future that increasingly seems to offer the sort of bleak and widespread old-age poverty that generally was eliminated by the Great Society. Income inequality reinforced by unequal security. Pile atop that a new — or rather, old — political inequality, such as the Roberts court seems to be fashioning, and it isn’t so much that America becomes unrecognizable, but that it becomes all too much so.

We’ve been here before and it was an unlovely place.

Blood and the lives and moral imaginations of our best people were spent to make it otherwise. To throw their courage and sacrifice away is moral and social profligacy that puts to shame any of the Gilded Age’s grotesque excesses.